Cooling apparatus



Sept; 6, 1938. D. w. R. MORGAN 2,129,097

I COOLING APPARATUS Original Filed Oct. 20, 1935 2 Sheets-Sheet 1 X o gm U I I, m 5 z E U U 3 I If 0 E f, INVENTOR Dnvm W.FE.MORGAN pd) a! [5: E ATTORNEY Sept. 6, 1938.

D. w. R. MORGAN 000mm APPARATUS Original Filed Oct. 20, 1955 2 Sheecs-Sheet 2 Khhd? OJOU INVENTOR Dnvn; \MRMonsnw BY 91 W ATTORNEY o mo uuwu m mokuuau NOFO Z U JU$ ROAR) robot 55$ 13,;

Patented Sept 6, 1938 PATENT OFFICE COOLING APPARATUS David W. R. Morgan, Swarthmore, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 20, 1933, Serial No. 694,510 Renewed February "I, 1935 22 Claims. (C1. 62-152) My invention relates to cooling apparatus of the type known as steam compressor or vaporjet refrigerating apparatus, and it has for an object to provide mechanism for controlling the operation thereof.

Steam jet refrigerating apparatus comprises an evaporating chamber into which liquid to be cooled is admitted, and one or more ejectors connected to the chamber for withdrawing vapor therefrom, thereby effecting a vacuum or reduced pressure in the chamber and consequent partial evaporation and cooling of the liquid therein. Inasmuch as an ejector is not well adapted for operation at partial load, a plurality of ejectors may be provided, which together provide the full refrigerating capacity, so that a smaller number of ejectors may be operated at partial load. A valve for each ejector may be provided, preferably between the evaporating chamber and the inlet of the ejector, which valve is closed when the ejector is shut down to prevent reverse How of vapor therethrough to the evaporating chamber, which reverse flow of vapor would destroy the vacuum therein.

In accordance with my invention, I provide control mechanism which, in initiating operation of an ejector, first admits motive fluid to the ejector to establish the suction or ejecting action of the ejector, the vapor valve between the evapo- 30 rating chamber and the ejector inlet being closed to prevent reverse flow of vapor into the evaporating chamber. After an intervalot time sui' flcient to assure that the ejecting action of the ejector has been established, the vapor valve is draw vapor from the evaporating chamber to effect refrigeration therein. In terminating operation of the ejector, the control mechanism effects closing of the vapor valve prior to or concurrently with shutting off of the motive fluid to the ejector, so that the passage through the ejector is open only when the ejecting action of the ejector is established, thereby preventing reverse flow of vapor therethrough into. the evaporating chamber.

The above and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings forming a part of this application, in which: Fig. 1 is a diagrammatic view of steam jet refrigerating apparatus to which my novel control mechanism is applied;

Fig. 2 is a wiring diagram of c0ntro1 sys opened, and the ejector is then eifective to withtem used in connection with the apparatus shown in Fig. 1; and

Fig. 3 is a wiring diagram of a further feature which may be applied to the control system of Fig. 2.

Referring to the drawings more in detail, I show, in Fig. 1, an evaporating chamber In of any suitable construction, adapted to receive water or liquid or other combinations of liquid and solids to be cooled. A conduit H is connected to the bottom of the chamber Ill for conveying the cooled water to the point of use. Three ejectors, designated A, B and C, have their vapor or suction inlets connected to the chamber l0. They are connected at their discharge ends to a condenser I! provided with an air ejector l3, condensate outlet I, cooling water inlet 8 and cooling water outlet 9.

Each ejector includes a nozzle chamber l4 and a converging-diverging conduit portion 15. Steam for motivating each ejector is suppled to the nozzles in the nozzle chamber thereof through a branch conduit l6, a valve I! being provided to control the flow of the motive fluid. The several branch conduits l6 are connected to a source of steam through a main conduit I 8. A vapor valve I9 is provided in the connection between the evaporator chamber l0 and the suction or vapor inlet of each ejector. A shut-oil valve 2| is provided between the discharge end of each ejector and the condenser II.

The ejectors A, B and C together provide the full refrigerating capacity of the apparatus when operating at full load. .For example, if the apparatus is designed for 300 tons capacity, each ejector may be designed to provide tons of refrigeration. Obviously, the refrigerating capacity may be divided among the ejectors in any desired proportions. The purpose of dividing the refrigerating capacity among a plurality of ejectors is to enable eilicient operation at partialload by operating only a portion of the total number of ejectors. For example, 200 tons of refrigeration may be effected by operating 2 ejectors, which, operating at full capacity, provide maximum efliciency.

when the motive steam to one ejector is shut off, the steam jets which normally efl'ect flow from the inlet to the outlet end of the ejector are discontinued, so that vapor may flow through the ejector in the opposite direction, that is, from the condenser to the evaporating chamber, due to diiference in pressure that exists between the evaporator and condenser. In order to prevent 5H0]: reverse flow of vapor through any ejector which is shut down, the vapor valve I9 is closed. The shut-off valves 2| are provided so that any one ejector may be isolated for repair by closing both its valves I9 and 2|.

The control mechanism for operating the ejector valves includes reversible split-field motors 22, 22, and 22 for operating the valves H of the ejectors A, B and C respectively, and similar reversible motors 23, 23 and 23 for operating the vapor valves l9 of the respective ejectors. The control mechanism further includes a thermostat 24 responsiveto the temperature of the water cooled in the chamber l0. Referring to Fig. 2, this thermostat preferably includes a thermostatic bulb 25 placed in the conduit I an expansible bellows 26 and a tube 21 connecting the same to the bulb 25. The bellows 26 is arranged to operate switches 28, 28 and 28 which are adapted to control the ejectors A, B and C, respectively.

Each switch includes a contact 29 connected to one line conductor, L1, and contacts 3| and 32 for initiating and terminating operation of the ejector, respectively. These switches may be of the mercury type, in which the mercury is adapted to connect the contacts 29 and 3| when tilted to the left for initiating operation of the control ejector, and to connect contacts 29 and 32 when tilted to the right for terminating action of the control ejector. The three switches 28 28, and 28 are arranged at varying angles so as to successively close the contacts for initiating operation of the respective ejectors upon expansion of the bellows 26 in response to successive increases inv temperature of the water being cooled, and to close the contacts for successively terminating operation of the several ejectors upon contraction of the bellows 26 in response to successive decreases in temperature or the water being cooled.

I preferably provide a drum controller for effecting operationof the valves l1 and I9 in the desired sequence and also for effecting the desired time delay between operation of the valves. Preferably, an individual drum controller is provided for each ejector, the ejectors A, B and C being provided with drum controllers 33*, 33 and 33, respectively. Each drum controller includes a drum 30 driven by a motor 34 through reduction gearing 35. The drum 3D is illustrated in. conventional developed view.

The drum controller 33 for the ejector A includes contact fingers 31, 38 and 39 and a segment 4| for controlling operation of the drum controller. The contact fingers 31 and 38- are connected to the contacts 3| and 32, respectively, of the thermostatic switch 28". The contact finger 39 is connected to one terminal of the motor 34, the other terminal thereof being connected to the line conductor L2. ment 4| is formed to connect the contact fingers 31 and 39 while the drum moves from off to on position, and to connect the contact fingers 38 and 39 from on to off position. The drum controller further includes a contact finger 42 connected to the line conductor L1, and contact fingers 43 and 44 connected to the valve opening field windings of the valve operating motors 22 and 23", respectively, and contacts 45 and 45 connected to the valve closing field windings of said respective motors. A segment 41, located between the ofi and on positions of the drum,

is formed as shown on the drawings to connect. the contact fingers 42 and 43 immediately after the drum leaves the off position, and to con- The seg-' 45 immediately after the drum leaves the on position, and to connect the contact fingers 42 and 45 at the end of a predetermined interval of time thereafter.

The drum controller 33 for operating the valves 22 and 23 of the ejector B and the drum controller 33 for operating the valves 22 and 23 of the ejector C are identical with the drum controller 33 described above.

The remaining terminal of each valve operating motor is connected, as shown on the drawings, to the line conductor L2. Each of the field windings is provided with a limit switch 49 for terminating operation of the motor upon completion of the valve movement. Cut-out switches 5|, 52 and 53 are provided in the conductors between the contacts 3| and 41 of the respective ejectors. Each switch is operated by the shutoff valve 2| the ejector, being opened whenever the shut-ofi valve is closed. In this manner, whenever the valve 2| is closed for isolating an ejector, the control mechanism for initiating operation of that ejector is rendered inoperative.

The operation of the above described apparatus is as follows: In the position shown on the drawings, the thermostat 24 is subjected to a temperature below the temperature at which the first ejector is placed in operation, and all of the ejectors are shut down. Assume now that, due to refrigerating load, the temperature increases sufiiciently to call for operation of one ejector. The expansion of the bellows 2B tilts the thermostatic switches to the left, the switch 28 being tilted sufiiciently that the mercury therein fiows to the left and connects the contacts 29 and 3|. The circuit is now completed for effecting operation of the drumcontroller 33 from the off to the on position, the circuit extending from line conductor L1, through contacts 29 and 3| of the thermostatic switch, through the cut-out switch contacts 31 and 39 and segment 4|, and motor 34 to the line conductor L2. The movement 01' the drum 30, as seen on the drawings, is'upwardly. Immediately after movement of the drum has begun, the bridging of the contacts 42 and 43 closes the circuit to the valve opening field winding and the armature of the steam valve motor 22, which opens the steam ,valve H for supplying steam to the nozzles 01' the ejector A. This circuit is traced as follows: From the line conductor L1 through the contacts 42 and 43 and the segment 41, and the valve opening field winding and armature of the motor 22 to the line conductor L2.

The drum 30 continues to rotate at a constant rate of speed, and at the end of a predetermined period of time, during which the ejecting action or suction of the ejector A is established, the segment 41 engages the contact member 44. A circuit through the valve opening field winding and armature of the vapor valve motor 23 is thus completed, the motor then operating to open the valve 9. At the end of a further period of time which is suflicient to permit opening of the valve I9 to be completed, the segment 4| disenand motor 34 to line conductor L2.

gages the contact finger 31, terminating further movement of the drum controller. At the same time, the segment 4! engages the'contact 38, thereby placing the drum controller in condition to be operated from on to off position when the thermostatic switch 28 is tilted in the opposite direction to bridge the contacts 25 and 32. The ejector A now operates to withdraw vapor from the evaporating chamber iii and to discharge the same into the condenser i2, thereby cooling the remaining water in the chamber iii, in the usual manner of steam jet refrigerating apparatus.

The apparatus is now operating to provide tons of refrigeration for cooling. If a greater amount of cooling is required, the temperature of the water will again increase to a higher temperature, in response to which the thermostat 24 will tilt the thermostatic switch 38 to the left and initiate operation of the ejector E in the same manner set forth above. Likewise, a still further increase in temperature will result in the thermostatic switch 28 effecting operation of the ejector C.

When the refrigerating load again decreases, the thermostatic switches 28, 28, and 28 operate in response to successively lower predetermined minimum temperatures to terminate operation of the ejectors C, B, and A. Operation of each ejector is terminated in the following manner:

Assume that the ejector A is in operation and that the temperature of the water decreases below a predetermined minimum temperature, indicating that further coolingaction is not presently required. The thermostat 24 then tilts the switch 28 to the right, causing the mercury to .bridge the contacts 29 and 32. A circuit to the motor 34 is then completed, extending from line conductor L1 through contacts 29 and 32 of the switch 28, contact 38, segment 4i, contact 39, The drum 30 now moves from its "on position to the "off position. Immediately after leaving the on" position, the segment 48 bridges the contacts 42 and 46, thereby completing a circuit to the valve closing field winding of the vapor valve motor 23, effecting operationpf the motor to close the valve l5. At the end of a predetermined interval of time thereafter, suflicient to assure complete closing of the valve. IS, the segment 48 connects the contact fingers 42 and 45, completing a cirwit to the valve closing field winding of the steam valve motor 22, whereupon the motor 22' operates to close the steam valve i! of the ejector A. Closing movement of the valves l9 and I1 is completed by the time that the drum 30 reaches the "off" position, at which the segment 4i disengages the contact 38 to discontinue movement of the drum and engaging the contact 31 to render the drum controller operable for againinitiating operation of the ejector.

If it is desired to isolate one of the ejectors for service or repair, the valve 2| of that ejector is closed. For example, assume that it is desired to isolate the ejector B. Closing the valve 2i 01" that ejector automatically opens the cut-off switch 52, thereby rendering the drum controller 33 for that ejector inoperable. In this case, if

the temperature of the water discharged through the conduit ll rises to call for operation of a second ejector, the thermostat 24 will tilt the switch 28 to connect the contacts 29 and 3|. Upon failure of the ejector B to start, the continued refrigeration load not provided for will effect further increase in temperature, in response to which the thermostat 24 will tilt the switch 28 to initiate operation of the ejector C. In this way, isolation of one ejector will automatically cause the next ejector in series to be operated to supply the required refrigeration load, although, in this case, a slightly higher temperature will be obtained.

In Fig. 3, I show a modified switch arrangement which may be used in place of the cut-out switches 5!, 52 and 53, whereby, when any one ejector is isolated, the operation of the succeeding ejectors is advanced one step. The relation of Fig. 3 to the remainder of the control mechanism may be readily seen by placing Fig. 3 over the thermostatic and cut-out switches of Fig. 2. The switches 51! 52', and 53 are operated by the valves 2i of the ejectors A, B, and C, respectively, each being moved to its upper position when the valve is opened and downwardly when the valve is closed. The switch 5i includes contacts 54 and 55 adapted to connect the contacts 3! and 32 of the thermostatic switch 28 to the contact The switch 52 includes contacts 55 and 65 adapted to connect the conductors 58 and 51 to the controller 35 in the upper position and to the controller 33 in their lower position. It further includes contacts 61 and 68 adapted to connect the conductors 6i and 62 to the controller 33 in their upper position. The switch 53' merely open-circuits the conductor connected to the contact 31 of the controller 33 to prevent operation of the ejector C from being initiated, there being no further ejectors to be operated when ejector C is isolated.

The operation of the arrangement shown in Fig. 3 is as follows: When all of the ejectors are in operation and the valves 2i are opened, the switches 5|, 52', and 53' are in their upper positions. The thermostat 28 controls the ejector A, since the contacts 54 and 55 connect the switch 28 to the controller 33. The switch 28 controls the ejector B, the contacts 58 and 59 connecting the switch to the conductors 58 and 51 which are, in turn, connected through the contacts 65 and 56 to the controller 33 The switch 28 controls the ejector C, since the movable contacts 63 and 64 connect the switch to the conductors (if and 62, which are in turn connected through the movable contacts 61 and 68 to the controller 33, the switch 53' being closed to permit operation of the ejector C.

If, now, the ejector A is isolated, the movable contacts of the switch 5| are moved to their lower positions. The operation of the ejectors B and C is now advanced one step, these ejectors responding to switches 28 and 28', respectively, instead of switches 28 and 28, respectively. This is due to the fact that the movable contacts 54 and 55 connected to the switch 28 now engage the conductors 56 and 51, which connect with the controller 33 through the movable contacts 65 and 8B, and to the fact that the movable contacts 58 and 59 connect the switch 28 to the conductors 6| and 62 which control the controller 33 through the movable contacts 61 and 68. Assume now that the ejector B is also isolated by closing its valve 2|, causing the switch 52' to be moved downwardly. In this case, the switch 18 controls the ejector C, being connected to the controller 33 through the movable contacts 54 and 55, the conductors 56 and 51, and the movable contacts 65 and 66.

Assume that the ejectors A and C are operable but that the ejector B is isolated, the switch 52' being in its lower position. In this case, the switch 28 controls the ejector A, but the switch 28 controls the ejector C, the thermostat 28 being connected through the movable contacts 58 and 59, the conductors 56 and 51, and the movable contacts 65 and 65 to the controller 33. When the ejector C is isolated, the switch 53' merely prevents operation of the ejector C, there being no further ejectors to be placed in operation.

In the arrangement shown in Fig. 8, it will be noted that, when any one ejector is isolated, the operationof all the succeeding ejectors in operation is advanced one step, while any preceding ejector not isolated is not affected thereby. With this arrangement, when the refrigerating load requires operation of say two ejectors, operation of that number of ejectors, if available, is effected without waiting for a higher temperature than is otherwise required to effect operation of the first two ejectors.

From the above description, it will be seen that I have provided control mechanism whereby operation of one or more ejectors may be controlled in such a way that reverse flow through any ejectors not in operation is prevented. This is effected by closing the vapor valve, that is, the valve between the evaporating chamber and the ejector, at all times that the ejecting action or suction of the jets in the ejector is not established.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so obvious but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, fluid translating means for withdrawing vapor from said chamber, means for controlling the admission of motive fluid to said translating means, means for controlling the fiow of vapor from the chamber to the fluid translating means, and means for operating the motive fluid controlling means first and the vapor flow controlling means last when initiating operation of the fluid translating means'and the vapor fiow controlling means first and the motive fluid controlling means last when terminating operation of the fluid translating means.

2. In cooling apparatus, the combination or an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, fluid translating means for withdrawing vapor from said chamber, means for controlling the admission of motive fluid to said translating means, means for controlling the flow of vapor Irom,the chamber to the fluid translating means, and means responsive to a condition of the cooled liquid for operating the motive fluid controlling means first and the vapor flow controlling means last when initiating operation of the fluid translating means,

said condition responsive means being effective to operate the motive fluid controlling means and the vapor flow controlling means, the latter at least as early as the former, when terminating operation 01' the fluid translating means.

3. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, fluid translating means for withdrawing vapor from said chamber, means for controlling the admission of motive fluid to said translating means, means for controlling the flow of vapor from the chamber to the fluid translating means, and means responsive to-a condition of the cooled liquid for operating the motive fluid controlling means first and the vapor flow controlling means last when initiating operation of the fluid translating means and the vapor flow controlling means first and the motive fluid controlling means last when terminating operation of the fluid translating means.

4. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, an ejector for withdrawing vapor from said chamber, means for controlling the admission of motive fluid to said ejector, means for controlling the fiow of vapor from the chamber to the ejector, and means for operating the motive fluid controlling means first and the vapor flow controlling means last when initiating operation of the ejector and the vapor flow controlling means and the motive fluid controlling means, the former at least as early as the latter, when terminating operation of the ejector.

5. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, an ejector for withdrawing vapor from the chamber, means for controlling the admission oi motive fluid to the ejector, means for controlling the flow of vapor from the chamber to the ejector, and means for automatically operating the motive fluid controlling means first and the flow controlling means second when initiating operation of the ejector and the flow controlling means first and the motive fluid controlling means second when terminating operation of the ejector.

6. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, an ejector for withdrawing vapor from the chamber, means for controlling the admission of motive fluid to the ejector, means for controlling the flow of vapor from the chamber to the ejector, means responsive to a condition of the cooled liquid for operating the motivefluid controlling means first and the vapor flow controlling means second when initiating operation of the ejector and the flow controlling means and the motive fluid controlling means, the former at least as early as the latter, when terminating operation the ejector.

7. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, an ejector for withdrawing vapor from the chamber, means for controlling the admission of motive fluid to the ejector, means for controlling the flow of vapor from the chamber to the ejector, and means responsive to a condition of the cooled liquid for operating the motive fluid controlling means first and the vapor flow controlling means second when initiating operation of the ejector and the flow controlling means first and the motive fluid controlling means second when terminating operation of the ejector.

3. In cooling apparatus, the cornbinationoLan fi V I evaporator chamber adapted to receive liquid to be partially evaporated and cooled, an ejector for withdrawing vapor from the chamber, a valve for controlling the admission of motive fluid to the ejector, a valve for controlling the flow of vapor between the chamber and the ejector, andmeans responsive to a predetermined maximum temperature of the cooled liquid for opening said valves and including time delay means for delaying opening of the vapor valve for a predetermined period of time after opening of the motive fluid valve and responsive to. a predetermined minimum temperature for closing said valves.

9. In cooling apparatus, the combination of an evaporator chamber adapted to receive liquid to be partially evaporated and cooled, an ejector for withdrawing vapor from the chamber, a valve for controlling the admission of motive fluid to the ejector, a valve for controlling the flow of vapor responsive to a predetermined maximum temperature of the cooled liquid for opening said valves and including time delay means for delaying opening of the vapor valve for a predetermined period of time after opening of the motive fluid valve, and responsive to a predetermined minimum temperature for closing said valves and including time delay means for delaying closing of the motive fluid valve for a predetermined period of time after closing the vapor valve.

10. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, a plurality of ejectors for withdrawing vapor from said chamber, a condenser for condensing vapor discharged by said ejectors, at least one of said ejectors having a pair of valves associated therewith and including one valve for controlling the admission of motive fluid to the ejector, and a second valve for controlling the flow of vapor from the chamber to the ejector, and means for opening the first and second-mentioned valves sequentially in the order named when initiating'operation of the ejector, and for closing said first and second-mentioned valves sequentially in the reverse order when terminating operation of the ejector.

11. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, a plurality of ejectors for withdrawing vapor from said chamber, a condenser for condensing vapor discharged by said ejectors, a plurality of valves.

associated with each of said ejectors and including one valve for controlling the admission of motive fluid to each ejector and a second valve for controlling the flow of vapor from said chamber to each ejector, and means for controlling the operation of the ejectors and including means for before opening the second-mentioned valve thereof when initiating operation of the ejector, and closing the second-mentioned valve of the ejector before closing the first-mentioned valve thereof when terminating operation of the ejector.

12. In cooling apparatus, the combination of an evaporating chamber'adapted to receive liquid to be partially evaporated and cooled, a plurality of ejectors for withdrawing vapor from said chamber, a condenser for condensing vapor discharged by said ejectorspa plurality of valves associated with each of said ejectors and including one valve for controlling the admission of motive fluid to each ejector and a second valve for controlling the flow of vapor from said chamber to each ejector, and means responsive to a condition of the cooled liquid for controlling the operation of the ejectors and including means for opening the first-mentioned valve of each ejector before opening the second-mentioned valve thereof when initiating operation of the ejector, and closing the second-mentioned valve of the ejector before closing the first-mentioned valve thereof when terminating operation of the ejector.

13. In cooling apparatus, the combination of aneva'porating chamber adapted to receive liquid to be partially evaporated and cooled, a plurality of ejectors for withdrawing vapor from said chamber, a condenser for condensing vapor discharged by said ejectors, a plurality of valves associated with each of said ejectors and including one valve for controlling the admission of motive fluid to the ejector and a second valve for controlling the flow of vapor from said chamber to the ejector, and means for initiating and terminating operation of the ejectors in sequence, and including means for opening the first mentioned valve of each ejector before opening the second mentioned valve thereof when initiating operation of the ejector, and closing the second mentioned valve of the ejector before closing the first mentioned valve thereof when terminating operation of the ejector.

it. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and .cooled, a plurality of ejectors for withdrawing vapor from said chamber, a condenser for condensing vapor discharged by said. ejectors, a plurality of valves movable to closed positions for respectively isolating the ejectors from the condenser, means responsive to the temperature of the cooled water for automatically initiating and terminating operation of the ejectorsin sequence, and means operated by the valves when closed for discontinuing the control of their respective ejectors by said temperature responsive means.

15. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, a plurality of ejectors for withdrawing vapor from said chamber, a condenser for condensing vapor discharged by said ejectors, a plurality of valves movable to closed positions for respectively isolating the ejectors from the condenser, means responsive to the temperature of the cooled water for initiating and terminating operation of tlie ejectors step by step, and means for advancing by one step the operation of succeeding ejectors when a preceding ejector is isolated from the condenser by the closing of its associated valve.

16. In cooling apparatus, the combination of an evaporating chamber adapted to receive liquid to be partially evaporated and cooled, a plurality of ejectors arranged in parallel for withdrawing vapor from the chamber, a condenser for condensing vapor discharged by said ejectors, a plurality of valves associated with each ejector including a valve for controlling the flow of motive fluid to the ejector, a second valve for controlling the flow of vapor from the chamber to the ejector and a third valve for isolating the ejector from the condenser, means responsive to the temperature of the cooled liquid for initiating and terminating operation of the ejectors, step by step, and including .means for sequentially opening the first and second-mentioned valves in the order named when initiating the operation of an ejector and for closing said first and second valves in a reverse order when terminating operation of an ejector and means for advancing by one step, 4

the operation of succeeding ejectors when a preceding ejector is isolated from the condenser by the closing of its associated valve.

17. Apparatus for supplying a refrigerating demand comprising evaporator means adapted to contain liquid to be evaporated, a plurality of ejectors for withdrawing vapor from said means to efiect cooling by evaporation of liquid therein, and means for automatically efiecting successive increases in total ejector capacity in operation in response to successively higher temperatures of liquid in said evaporator means, respectively.

18. In cooling apparatus, the combination of evaporator means, a plurality of compressor elements for removing vapor from said evaporator means to effect cooling by evaporation of liquid therein, said evaporator means and said compressors supplying a common cooling demand, a thermostatic element responsive to a temperature maintained at a low value by the cooling apparatus, and means controlled by said thermostatic element and operating automatically to initiate operation of said compressors successively as said temperature attains successively higher values.

19. In cooling apparatus, the combination of evaporator means, a plurality of compressor elements for removing vapor from said evaporator means to effect cooling by evaporation of liquid therein, said evaporator means and said compressor elements supplying a common cooling demand, and means for controlling said compressor elements including a thermostatic element responsive to a temperature maintained at a low value by the cooling apparatus, and a plurality of electric switches actuated by said thermostatic element for controlling said compressor elements, respectively, said switches being arranged to be closed in sequence by said thermostatic element as the latter responds to successively higher values of said temperature.

20. Cooling apparatus for supplying a refrigerating demand comprising evaporator means adapted to contain liquid to be evaporated, a plurality of ejectors for withdrawing vapor from said evaporator means to efl'ect cooling by evaporation of liquid therein, and means for controlling said ejectors including a thermostatic element responsive to the temperature of cooled liquid in said evaporator means and means controlled by said thermostatic element for increasing the number of ejectors in operation as said thermostatic element responds to increase in said temperature and vice versa.

21. Cooling apparatus for supplying a refrigerating demand comprising evaporator means adapted to contain liquid to be evaporated, a plurality of ejectors for withdrawing vapor from said evaporator means to effect cooling by evaporation of liquid therein, and means for controlling said ejectors including a thermostatic element responsive to the temperature of cooled liquid in said evaporator means and a plurality of electric switches actuated by said thermostatic element for controlling said ejectors, respectively, said switches being arranged to be closed in sequence by said thermostatic element as the latter responds to successively higher values of said temperature.

22. In cooling apparatus of the vapor jet type, the combination of an evaporator chamber, means for delivering liquid to be cooled to said chamber, means for removing cooled liquid from said chamber, a plurality of ejectors for removing vapor from said chamber to eifect cooling of the liquid therein by partial evaporation thereof, one of said ejectors having a motive fluid admission valve and a vapor valve controlling flow of vapor from said chamber to said ejector, and means for controlling said valves of said one ejector in response to a load condition of the apparatus, said last-named means being operable, upon initiating operation of the ejector, to open said vapor valve only when said admission valve is open and the ejecting action of the ejector is established, and being operable, upon terminating operation of the ejector, to close said admission valve only when the vapor valve is closed.

DAVID W. R. MORGAN. 

